Question

(2/7)(∛-343)-(1/4)(∛40)+(1/2)∛135
Simplify, if possible.

Answer 1

\[2\sqrt[3]{-1}+ \sqrt[3]{5}\]

Answer 2

dang, not it....

Answer 3

are you looking for it as a minimal polynomial?
x^6-6x^5+24x^4-66x^3+126x^2-36x+9

Answer 4

Simplify if possible - is the only instruction...

Answer 5

is this the problem?

Answer 6

yep, u got it!

Answer 7

then what i said first should be the answer...

Answer 8

³√5-2
^
was the right answer:) thnks though!

Answer 9

1) You need to factor out somethings from the cubed roots. If you look at ³√40 and ³√135 you'll notice that they can be broken up into the following:
³√40 = ³√5 * ³√8
³√135 = ³√5 * ³√27
Since 8 and 27 are perfect cubes 2 and 3 respectively, the above can be reduced to
³√40 = 2³√5
³√135 = 3³√5

2) Place the above values into the equation and simplify down
(2/7)³√-343 - (1/4)*2*³√5 + (1/2)*3*³√5
(2/7)³√-343 - (2/4)*³√5 + (3/2)*³√5

3) 343 is a perfect cube which reduces to -7, i.e.
³√-343 = -7

4) Place the above in for ³√-343 in the equation and simplify down again
(2/7)(-7) - (2/4)³√5 + (3/2)³√5
-2 - (2/4)³√5 + (3/2)³√5
-2 - (1/2)³√5 + (3/2)³√5

5) Notice that the tail end of the expression ((2/4)³√5 + (3/2)³√5) have both a ³√5 and a (1/2) in common in both terms. Pull these out using the distributive property.
-2 - (1/2)*³√5*(1+3)
-2 - (1/2)*³√5*(4)
-2 - 2*³√5

6) Now there is a 2 and a -1 in common with both terms in the final expression above, pull those out in front
-2*(1+³√5)

That should be the answer. Unless a paren or something was missing from the problem, I'm not sure how you got ³√5-2